Local 400 represents workers at the R.I. Departments of Transportation and Environmental Management and is one of 205 plaintiffs suing to overturn the pension law. The union did not respond to an email request for comment about the vote or answer a phone call on Tuesday.

All the parties involved in the pension lawsuit have been placed under a gag order by R.I. Superior Court Judge Sarah Taft-Carter, who is overseeing the case. The order bars them from speaking with reporters about the settlement process. The deadline for current employees to finish voting on the settlement is Friday.

At stake in the suit is whether Rhode Island legislators acted constitutionally three years ago when they reduced future retirement benefits to shave roughly $4 billion off the shortfall in the state’s pension fund for government workers and taxpayers.

Former R.I. Supreme Court Chief Justice Frank Williams, appointed the case’s special master by Taft-Carter, has worked with lawyers on both sides of the case to put together a new settlement proposal in recent weeks. Retirees voted overwhelmingly in favor of the deal on Monday, after they said Williams told them they were likely to lose the case.

The significance of Local 400’s vote against the settlement remains unclear. State and union leaders have not provided details on the rules governing the voting and approval process for the settlement, saying the judge’s gag order bars them from doing so.

A previous effort to settle the lawsuit collapsed last April when 61% of eligible police officers voted to reject the proposal. That settlement effort divided all current and retired employees in the pension system into six subgroups, with the police being one of the six; the state refused to settle with the five subgroups who had voted to accept the deal once the police voted no.

Due to the gag order, officials have not said whether each individual union’s vote will determine whether its members accept or reject the settlement, or if each union’s vote will be combined with those of others in a larger subgroup before they are officially counted, as happened last time.

Robert Walsh, executive director of the National Education Association Rhode Island teachers’ union, told his members in a private email Monday that he doesn’t know whether the state is willing to settle with some groups if others reject the settlement. “It is unknown how the state will react if the same thing happens this time,” he wrote.

Separately, The Providence Journal reported Tuesday that members of Local 580 of the Service Employees International Union have voted to accept the pension settlement.